Self-cleaning filter



Aug. v14, 1945, N; oBENsH'AlN ET Al. 2,382,656

SELF-CLEANING FILTER Filed oct. 1e. 1942 2 sheets-sheet 1 WASH WA'TEIZ I COLOR OUT `W/'LSHv WATER A COLOR 1N i 2l z2 2 l ,a 34 24a /77 /7 y- Z l2 /8 ,230 33 Z4 Je 3/ l W 30 A /A I\\\\ \\I /5 'a -H--Q -l (more om' Aug. 14, 1945.

N. OBENSHAIN ET AL SELF-CLEANING FILTER 2 Sheets-Sheet 2 v Filed Oct. 16, 1942 s N E E 2 c 5 EHOVA BLE FILTER //LTON A. SII/EL),

Patented Aug. 14, 19.45

UNITED I STATES PATENT I OFFICE SELF-CLEANING FILTER Noel obonshoin, Piedmont,v w. vo., one Milton A.

Sively, Luke, Md., assignors to West Virginia Pulp and Paper Company, New York, N. Y., a

' corporation of Delaware Application October 16, 1942,' Serial No. 462,240

5 Claims.

Our present invention relates to self-cleaning filters having special application to the'iiltration of viscous liquids, as for example, those used as coating compositionsor colors for paper and other webs and which have high viscosity. Such liquids invariablyl contain a certain amount of grit and fibers of various kinds and origins, which, when present even in small quantities, interfere with the coating operation and cause streaks on the paper or other web. A further type of impurity which must either be removed or prevented from forming is ilakes of solid color which are formed by drying of the material and which subsequently do not revert to their original state of suspension but act in the manner of the grit already mentioned.v For this reason it is desirable that the' iilter be compact so that it may be mounted near the coating apparatus and that it vbe fully enclosed whereby no oportunity is had for the color to cake or dry out. Furthermore,

the loss of filtrate must be small.

It is therefore an object to provide a filter answering the above mentioned requirements which will be self-cleaning by providing for continuously backwashing the filtering elements. Further ad- Each casing element i3 I registering iilter chambers 24; 24a, respectively, chamberla communicating with an inlet duct 25, which in turn registers with duct 23a in cas.I ing element il. Similarly, casing section Il has a passage 28 for a wash water which registers with a `corresponding passage 26a in casing section I0, such passage terminating in opening 2l registering with ductv 21a in casing section Il.

Also, there is provided an exit passage '23 in casing section I i leading from the filter chamber 24. Labelled ,pipe connections 28', 25h, 26 and 2lb are shown in Fig. A1 for the inlet and outlet of liquid to be ltered and the inlet and outlet for the wash water.

Casingsection l I has journaied therein a shaft 30, such shaft passing through al stumng box 3| and having at the other end thereof splines 32 vantages of our improved device will be apparent hereinafter and the features of novelty will be pointed out in the appended claims. For the best understanding of our invention reference may now be had to the following detailed description taken with the annexed drawings, in which Fig. 1 is a. view in elevation showing the front end of an illustrative embodiment; l

Fig. 2 is a view in section taken along line 2-2 o! Fig. 1;

Fig. 3 is a view in .section taken along line 3-3' of Fis. 1. y

Fig. 4 is a view of an improved filter element employed;

rig. 5 is o view along imo t-s or Fig'. 4: 4

Fig. 6 is a view in perspective, somewhat diagrammatic, of the device showing parts'thereof separated.

Referring more particularly to Figs. 1 and (i, it

will be noted that our improved device includesy an exterior casing comprised of a head element I3 and a tail element I l which are adapted to be held together by means of a yoke I2 pivoted t0 element il by pivot I3 and carrying a screw bolt i5 and screw handle I8, such boit terminating in a head l` which engages within slot I3 of a lug i3 on tali element l0.; Casing element il has a rib or flange 2| which engages a recess 22 in element Hi, the surfaces in contact being machined to pro to receive a hub 33 of a iilter disc 34, the bore of hub33 being grooved to receive the splines 32. It will be evident that when the casing members l@ and Ii are clamped together, the chambers 24, 24a for the color or other liquid to be ltered and the wash passages 26, 26a are separated by the filter disc 34 whereby the liquor to be-lteredand the washing iiuid are constrained to pass through respective of the filter elements 33 arranged i radially of the hub 33, several of the lter discs being in simultaneous iiltering operation.y Bushings 38 and 38aA serve to keep the shaft 30 from longitudinal movement. llhe wash passage 23 terminates preferably in a narrow slit-type nozzie 31 in order that a stream of water of high pressure may be directed against the filter elements as they are moved by rotation opposite such jet. It will be further noted that the path of the liquor tobe filtered is in the. opposite direction to that of the wash water whereby the strained out particles on the filter elements are back washed and removed by the stream of wash water. i

struction oi the filter elements consisting of slots 33'in the filter disc 34, such slots being covered by a filter screen E which is held in place by 9 vide a tight iitting and leak-proof'container. 55

reinforced washer ring i (reinforcement lla) and Il is provided with and a snap ring I2 contained in a groove in the disc 84. This type of construction is an impor..

tant feature permitting easy replacement ofv screens and keeping thickness of the disc to'a minimum. For most cases the disc need not be more than thick. The small volume contained within the filtering elements result in minimum loss of filtrate in the back wash discharge. In order to permit the inspection of the alter elements without interrupting the operation of it is only necessary to reduce or shut off the flowV of wash liquid, removethe inspection door by looseningthe wing nut 41, and allow the nlter disc to rotate past the` opening, all without having to interfere with the flow of material being filtered. Also, .with suitable tools any filter element may be replaced through this inspection door by stopping rotation of the filter disc for not more than a short time. Since this operation can be performed quickly. it usually is not lnecessary to take the filter out of service.

It will beseen from Athe foregoing that our improved self-cleaning lter is compact and simple, requiring only two moving parts, the filter disc u and the shaft I; that the head element is removable by looseningthe clamp comprised of the handle, II, and that, moreover, the arrangement' of vthese parts is such that should the casing member il stick,;-it will be forcibly withdrawn upon continued screwing out of the bolt II due to the head I1 engaging in the slot'il. When the casing head is removed the lter disc Il may be readily removed from the shaft Il for servicing or for inspection of'.the washing jet l1.

It will be evident that various changes may be made in the speciilc'embodiment herein described, without departing from the spirit of our invention or the scope We claim: 1. A self-cleaning filter of the type having sepo'f the appended claims.

arate filter and wash passages and in which the operations of filtering and back washing are siinultaneouslyl performed, such filter comprising a. comparatively thin rotary iilter disc containing a plurality of filter elements which intercept the nlter and wash passages, a casing surrounding said filter disc comprising a first portion and a second portion separable on a'section parallel to the plane of said disc and affording access to same when said elements are separated, releasable means for holding said portions together, said first casing portion having an inlet and an outlet for iiuid to be filtered as well as an inlet and an `outlet for washing iiuid and passages for said fluids, said first section alsocontaining a drive shaft for mounting and rotating said-filter disc,

said second casing portion having passages whose ports register with corresponding ports in saidfirstV casing section for completing the circuits of the fluid undergoing filtration and said washing fluid.

2. A self-cleaning filter as per claim 1, in which the filter element consists of a perforated baclt-A ingsupport, a screen, a retaining plate, and moans for holding the retaining plate in place.

said items mentioned 'being mounted within the 4 thickness of the nlter disc.

3; A self-cleaning filter as per claim 1, in which said second casing section has an inspection door disposed so ,as to -atl'ord access to said lter elements and to the washing fluid passage and of a size sufficient to allow passage of said lter ele-f ments therethrough.

.4. A self-cleaning-iilter as'per claim l, in which l said lter disc is keyed to said drive shaft butV is removable therefrom endwise of the shaft.

5. .AH filter as per claim 1, in which the releasable means for holding the casing sections toi-- gether comprises a clamping yoke pivoted upon said first casing portilon and removably engag ing said second portion by means of a threaded .boit in said yoke having s puin and pun con- Nom. onnNsHArN. Ammon a sIvELY. 

